Many musicians seek the capability to create a very particular sound or “tone” and will go to great lengths and/or expense in order to produce it. Oftentimes the emulation of a particular tone, or in some cases, the ability to create new sounds is desired. In the context of electric guitar, many factors contribute to the sound of the instrument such as, for example, the type and quality of body material, stress state of the material, and type of transducer or “pickup” used.
Magnetic- and piezo electric-based pickups are the most common, but other methods have been demonstrated to convert the vibration of the strings into an electrical signal. Magnetic pickups are non-linear devices that serve not only to convert vibrations into electrical signals, but also can add tones not originally present in the electrical signal. This is due to, for example, the non-linear interaction of the steel string moving through the non-uniform magnetic field produced by the pickup's permanent magnets.
Electric guitar and bass pickups have been produced in different forms beginning in the 1930s. Many types of magnetic pickups have been produced through the years, which include variations in electromagnetic circuit topology. One of the most common distinctions made with modern day pickups is between “single coil” and dual coil “humbucking” types, which can each have distinctive sounds and can be formed in numerous ways.
A further distinction can also made between “passive” and “active” pickups. Passive magnetic pickups are unpowered and are typically formed from a number of turns of fine wire around a bobbin and some form of magnet. The signal chain of a passive pickup can make use of passive circuit elements such as capacitors, resistors, and potentiometers. In contrast, active pickups require power, but can utilize additional circuit elements such as, for example, operational amplifiers or other integrated circuits to filter and possibly amplify the signal.
In passive pickup configurations, the tone generated by the pickup is primarily set through the details of the electromagnetic circuit employed. Typically the number of turns of wire, magnetic field strength, diameter of wire used, and number coils are selected to produce a characteristic sound. These physical design characteristics translate to engineering parameters such as inductance, capacitance, and resistance. These engineering parameters together create a characteristic frequency response of the pickup, which can be represented through gain, resonant frequency, and circuit Q.
Often times a “tone control” potentiometer is included in (or on) the body of the guitar to give some tonal control (e.g., treble and/or bass) of the sound produced. Musicians, however, sometimes find this tone control insufficient in its ability to produce the desired sound, and resort to swapping various components, including pickups, or entire guitars to find something more to their liking.
Thus, a need exists for an improved musical instrument pickup.